- Journal of Biological and Chemical Research
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- Journal of Biological and Chemical Research
Isolation and Characterization of Lactic Acid Bacteria from Cabbage to Use as a Probiotic By Estifanos Hawaz and Teklemariam Guesh ISSN 0970-4973 Print ISSN 2319-3077 Online/Electronic Global Impact factor of Journal: 0.756 Scientific Journals Impact Factor: 2.597 Index Copernicus International Value IC Value of Journal 4.21 Poland, Europe J. Biol. Chem. Research Volume 32 (1) 2015 Pages No. 66-76 Journal of Biological and Chemical Research An International Journal of Life Sciences and Chemistry Indexed, Abstracted and Cited in Various National and International Scientific Databases of the World Published by Society for Advancement of Sciences® J. Biol. Chem. Research. Vol. 32, No. 1: 66-76, 2015 (An International Journal of Life Sciences and Chemistry) Ms 32/1/29/2015, All rights reserved ISSN 0970-4973 (Print) ISSN 2319-3077 (Online/Electronic) Estifanos Hawaz http:// www.jbcr.in [email protected] [email protected] RESEARCH PAPER Received: 02/12/2014 Revised: 25/12/2014 Accepted: 01/01/2015 Isolation and Characterization of Lactic Acid Bacteria from Cabbage to Use as a Probiotic Estifanos Hawaz and Teklemariam Guesh Department of Biology, College of Natural and Computational Sciences, Haramaya University, Ethiopia ABSTRACT The purpose of this study was to isolate and characterize lactic acid bacteria from cabbage sample and to evaluate its probiotic feasibility under conditions simulating human gastrointestinal (GI) tract. For this purpose a total of 15 cabbage samples were collected randomly from Haramaya district during the period from May to August, 2014. Microbiological analysis of each sample was done. Microbiological analysis comprised isolation of lactic acid bacteria, biochemical characterization, and probiotic feasibility test. According to biochemical test, Lactobacillus salivarius, Lactobacillus fermentum, Lactobacillus plantarum, Lactobacillus cellobiosus, and Lactobacillus brevis were isolated from cabbage sample. The probiotic effect of each isolate was evaluated for antimicrobial activity against pathogenic bacteria, resistance to bile acids, resistance to low pH, antibiotic resistance, and haemolytic activity. Results showed that all isolates produce antagonistic effect against pathogenic bacteria (P.aeruginosa, S.aureus, E.coli, and K.pneumonia) with different degree of inhibition zone. Among all isolates L.brevis shown more inhibition zone followed by L.cellobiosus and L.plantarum. According to resistance to bile; L.plantarum, L.cellobiosus and L.brevis were retaining their viability with negligible reduction but L.salivarius and L.fermentum were survived with significant (p<0.05) reduction in viable count. According to resistance to low pH; L.plantarum, L.cellobiosus, L.salivarius and L.brevis were able to survive at pH ranging from 2 to 4 with significant (p<0.05) reduction in viable count. Regarding to antibiotics resistance; L.plantarum, L.cellobiosus and L.brevis were resistant strains to Streptomycin, Gentamycin and Tetracycline antibiotics. According to haemolytic test all Lactobacillus isolates did not exhibited β–haemolytic activity when grown in Colombia human blood agar. In conclusion, the present study indicated that L.brevis and L.cellobiosus can be used as potential probiotic Lactobacillus strains. Key words: Cabbage, Probiotic, Pathogenic Bacteria and Gastrointestinal (GI) Tract. Isolation……………………………………………….………………Probiotic Ganguly, 2015 INTRODUCTION Lactic acid bacteria are a broad group of Gram positive, non-spore forming, catalasenegative, facultative anaerobic and nutritionally fastidious organism (Axelsson, 1998). They are widespread in soil, vegetables, meat, milk and the human body. Lactic acid bacteria (LAB) are among the most important groups of microorganisms used in food fermentation where they play an essential role and a wide variety of strains are routinely employed as starter cultures in the manufacture of dairy, meat, vegetable and bakery products (Noopur et al., 2010; Hassanzadazar and Ehsani., 2013). One of the most important contributions of these microorganisms is the extended shelf life of the fermented products. Growth of spoilage and pathogenic bacteria in these foods is inhibited due to competition for nutrients and the presence of starter-derived inhibitors such as lactic acid, hydrogen peroxide, diacetyl and bacteriocins (Noopur et al., 2010; Noordiana et al., 2013). Probiotics are defined as a live microbial feed supplement which beneficially affects the host animal by improving its intestinal microbial balance (Fuller, 1989). It is well established that probiotics confer a number of beneficial health effects to humans and animals. Intake of probiotics stimulates the growth of beneficial microorganisms and reduces the amount of pathogens improving thus the intestinal microbial balance of the host and lowering the risk of gastro-intestinal diseases (Chiang and Pan, 2012), alleviation of lactose intolerance, the enhancement of nutrients bioavailability, and prevention or reduction of the prevalence of allergies in susceptible individuals (Chiang and Pan, 2012; Isolauri, 2001). Probiotics are reported to have also antimutagenic, anticarcinogenic, hypocholesterolemic, antihypertensive, anti-osteoporosis, and immunomodulatory effects (Chiang and Pan, 2012). They relieve the symptoms of inflammatory bowel diseases, irritable bowel syndrome, colitis, alcoholic liver disease, constipation and reduce the risk for colon, liver and breast cancers (Prado et al., 2008). In the past years, a lot of work was done to isolate and characterize lactic acid bacteria from different sources but the probiotic properties of these lactic acid bacteria strains were not well determined. The purpose of this project was to isolate and characterize lactic acid bacteria from locally available cabbage samples and to evaluate its probiotic properties under conditions simulating human gastrointestinal (GI) tract. MATERIAL AND METHODS Description of the study area Haramaya district is one of the woredas in the Oromia Region of eastern Hararghe, Ethiopia. The altitude of this district ranges from 1400 to 2340 meters above sea level. Haramaya District located about 500 Km distanced from Addis Ababa, Ethiopia. Experimental Design The laboratory analysis of the study was carried out at Microbiology laboratory of Haramaya University, Ethiopia, during the period from May to August, 2014. Sampling frame consisted of local places participated in selling and utilizing cabbage. Accordingly, a total of 15 samples of cabbage were collected randomly during the period from May to August, 2014. The laboratory examination comprised isolation of lactic acid bacteria, biochemical characterization, and probiotic feasibility test. J. Biol. Chem. Research 67 Vol. 32, (1): 66-76 (2015) Isolation……………………………………………….………………Probiotic Ganguly, 2015 The experiment was conducted in duplicate. Complete randomized design with ANOVA techniques was used to data analysis. Significant differences (p<0.05) of means were separated using least significant differences (SLD). The General linear model (GLM) procedure of latest version (9.1.3 of SAS) was used. Data and sample collection Data was collected during laboratory analysis. Cabbage samples were collected from Haramaya University student cafeteria (HUSC), Haramaya town market (HaTM) and also from Bate town market (BaTM) of the Haramaya districts. The cabbage samples were taken in accordance with the instructions given in Health Protection Agency (HPA, 2004) and the Food and Drug Administration (FDA, 2003). Cabbage sample were packaged into sterile plastic containers, transported to the laboratory and processed immediately to prevent deterioration (HPA, 2004). Isolation of lactic acid bacteria (LAB) Enrichment was done by taking one grams of each sample were weighed aseptically and homogenized in nine ml of sterile salt solution (0.1% NaCl) using the vortex. Then, sequential decimal dilutions of the homogenate were obtained. One ml of each aliquot dilution was spread plated on MRS agar and M17 agar, for the isolation of lactic acid bacteria and incubated anaerobically for 48 h at 37°C. Colony counting was performed using colony counter (Bukola et al., 2008).The colonies were randomly picked from plate and purified by successive streaking on MRS agar media before being subjected to characterization. Gram-positive and catalase-negative isolates were isolated and characterized by phenotypic criteria (Harrigan and McCance, 1990), stored in glycerol and kept for further investigation at -20°C. Physiological and biochemical characterization of lactic acid bacteria (LAB) Growth of lactic acid bacteria (LAB) isolates was examined in MRS broth at temperature 15, 37 and 45oC for 24h anaerobically (Briugs, 1953). CO2 and lactic acid production from glucose was tested in citrate lacking MRS broths media containing inverted Durham tubes. Salt tolerance was tested in MRS broth by incorporating at 2%, 4% and 6.5 % (w/v) sodium chloride, incubated at 30oC was carried out according to method described by (Briugs, 1953). Catalase test was performed by adding 3% of hydrogen per oxide (H2O2) in a test tube containing an overnight culture of lactic acid bacteria. Ammonia production in MRS broth containing 0.3% arginine and 0.2% sodium citrate instead of ammonia citrate and the production of ammonia was detected using Nessler’s reagent (Briugs, 1953). The strains were further characterized by their carbohydrate fermentation pattern using different sugars included lactose, raffinose, sucrose, salicine, cellobiose, gluconate, arabinose, and mellibiose. Gram positive, catalase negative, and bacilli colonies were taken as presumptive lactic acid bacteria and stored in glycerol culture and kept at -4°C for further investigation. Probiotic feasibility test of Lactobacillus isolates All lactic acid bacteria isolates were examined their probiotic properties under conditions simulating human gastrointestinal (GI) tract included, antibiotic resistance, and resistance to low pH, resistance to bile acids, haemolytic activity and antimicrobial activity against pathogenic bacteria. Resistance to low pH and resistance to bile acids were determined according to reduction in viability (log cfu/ml) comparing with the reference microbial count. Accordingly, 2.8log cfu/ml was used as a reference of all lactic acid bacteria isolates. J. Biol. Chem. Research 68 Vol. 32, (1): 66-76 (2015) Isolation……………………………………………….………………Probiotic Ganguly, 2015 Antibiotic resistance All lactic acid bacteria isolates were evaluated their antibiotic resistance by disk diffusion method using three different antibiotics (streptomycin, tetracycline and gentamycin). Six milliliter of overnight growing culture were inoculated in to MRS broth and mixed thoroughly using vortex and spread plated over MRS agar in triplicates. After solidification of the media, the antibiotic disk were kept on the solidified agar surface and the plate were left over for 10 minute at 4oC for diffusion of antibiotics and then anaerobically incubated at 37oC for 48 h. zone of inhibition was measured by calipers in millimeter (Todorov and Dicks, 2004). Resistance to low pH Lactic acid bacteria isolates were assessed their resistance to pH 2.0, 3.0, and 4.0 incubated anaerobically at 37oC for 3 h. All overnight grown lactic acid bacteria culture with 2.8log cfu/ml was used and Cells were harvested by centrifugation (5000 rpm for 10 min at 4°C). Pellets were washed once in phosphate-saline buffer (PBS at pH 7.0). Then cell pellets were suspended in with different pH ranges and incubated at 37°C. Enumeration of viable colony on MRS agar was carried out using colony counter at the 3 h. Resistance against bile Resistance to bile acids was carried out using all overnight grown lactic acid bacteria culture with 2.8log cfu/ml and spread plated on MRS agar containing 0.3% (w/v) bile concentration in triplicates and incubated anaerobically at 37oC for 4 h (Kumar, 2012). Enumeration of viable colony on MRS agar was carried out for every hour with spread plate technique using colony counter. Haemolytic activity Lactic acid bacteria isolates were screened for haemolytic activity on blood agar plates containing 5% sheep blood and incubated at 37°C for 48 h. Haemolytic activity of the culture was evaluated for signs of β-haemolysis, γ-haemolysis and α-haemolysis on human blood agar plates (Nour-Eddine, 2006). Antibacterial activity of Lactobacillus isolates Antimicrobial effects of presumptive strains of Lacctobacillus spp. were determined by the agar diffusion method (Todorov and Dicks, 2004). Lactic acid bacteria isolates were evaluated for antimicrobial activities against pathogenic bacteria (P.aeruginosa, S.aureus, E.coli, and K.pneumonia) were obtained from Haramaya University Microbiology laboratory. The tested lactic acid bacteria were inoculated in to MRS broth and incubated at 37°C for 48 h. Cell free supernatant and cell mass were screened for antibacterial activity against the pathogenic bacteria. Cell free supernatant was obtained by centrifugation of the liquid culture (8000 rpm for 20 minutes at 4°C). Six milliliters diameter wells were loaded with 15μl of the cell free supernatant. Wells were prepared in the Mueller Hinton agar previously seeded with the test isolates. The plates were then incubated at 37°C for 24 h after which the diameter of inhibition zones was determined using calipers in millimeter (Todorov and Dicks, 2004). J. Biol. Chem. Research 69 Vol. 32, (1): 66-76 (2015) Isolation……………………………………………….………………Probiotic Ganguly, 2015 RESULTS AND DISCUSSION Isolation of lactic acid bacteria (LAB) A total of 65 isolates were obtained from 15 cabbage samples, 23 isolates of them shared characteristics of lactic acid bacteria (LAB) which are gram positive, catalase negative, none motile, none sporulating, anaerobic bacteria and appeared as bacilli under the microscope as shown in (Table 1). Table 1. Morphological and cultural characteristics of lactic acid bacteria isolates. Spore Capsule Motility Shape Sample source Identification forming of cell HUSC Lactobacillus spp., Bacilli N N N HaTM Lactobacillus spp., Bacilli N N N BaTM Lactobacillus spp., Bacilli N N N N negative Table 2. Lactobacillus isolates from cabbage. Sample Sample source Lactobacillus strains areas HUSC Cabbage Lactobacillus salivarius, Lactobacillus fermentum, Lactobacillus plantarum and Lactobacillus cellobiosus HaTM Cabbage Lactobacillus plantarum, Lactobacillus brevis and L. cellobiosus BaTM Cabbage Lactobacillus fermentum, Lactobacillus plantarum and Lactobacillus cellobiosus Physiological and biochemical characterizations of LAB isolates According to biochemical characterization, 11 isolates were Lactobacillus cellobiosus, 8 isolates were Lactobacillus plantarum, and three isolates were Lactobacillus salivarus, Lactobacillus fermentum and Lactobacillus brevis. All isolates were well classified based on their sugar fermentation test. Lactobacillus cellobiosus was the dominant bacteria isolated in all the cabbage samples. Similar report by (Hernández et al., 2005) were isolated L. plantarum from cucumber fermentation and (Daeschel et al., 1990), were isolated L. plantarum from Italian ewe cheeses, Hassanzadazar and Ehsani., (2013) reported that the dominant isolated bacillus genus from Koopeh Cheese was Lactobacillus plantarum (58% of lactobacilli population). L. fermentum were isolated from samples collected from BaTM and HUSC. Lactobacillus salivarus were isolated only from samples collected from HUSC. All isolates were able to grow at 37 oC and 45oC, (Table 3). Similar report by (Iman A et al.,2014) two isolates L. plantarum K3 and L. plantarum SH4 and L. fermentum C12 were able to grow at 45oC, while 12 isolates weren’t able to grow at the same temperature (Table 3). As shown in (Table 3) all isolates were able to grow in the range of 2 to 4% NaCl concentration. The growth of two L. plantarum isolates isolated by (Vijai Pal et al., 2004) showed very weak growth in the presence of 4% NaCl concentration. All tested isolates did not produce ammonia from arginine. J. Biol. Chem. Research 70 Vol. 32, (1): 66-76 (2015) Isolation……………………………………………….………………Probiotic Ganguly, 2015 This is comparable with Estifanos H, (2014) who reported that all isolates of lactic acid bacteria from curd did not produce ammonia. L. plantarum and L. fermentum isolates were produced CO2 gas from glucose, and all isolates are catalase negative as show in Table 3. Table 3. Physiological and biochemical characteristics of the LAB isolates. Lactobacillus strains Tastes L.brevis L. salivarius L.fermentum L. plantarum L. cellobiosus Growth at 15 oc o 37 c + + 45oc + + PH 2.0 + + 3.0 + + 4.0 + + Co2 production Ammonia >> Lactic acid >> + + Sodium chloride 2% + + 3% + + 4% + + Catalase test Sugar fermentation Lactose + + Raffinose Sucrose + Salicine + + Cellobiose Gluconate Arabinose Mellibiose + _ V Positive, negative and variable + + + + + + + + + + + + + + + + + + + + + + - + + + - + + + - + + + + V + V + - + + + V Probiotic feasibility test of Lactobacillus isolates Resistance to low pH All selected Lactobacillus isolates were examined for pH resistance. Results showed that, L.plantarum, L.cellobiosus, L.salivarius and L.brevis were able to survive at pH ranging from 2 to 4 with significant reduction in viability but L.fermentum isolate was able to survive only at pH 4 as shown in Table 4. J. Biol. Chem. Research 71 Vol. 32, (1): 66-76 (2015) Isolation……………………………………………….………………Probiotic Ganguly, 2015 Similar report by Estifanos H, (2014) has shown that L.casei and L.delbrueckii strains isolated from curd were survived at pH 3.0. Our results were also similar to (Martin et al., 2004) who isolate L.gasseri, L.fermentum and L.brevis from human milk that can survive at low pH. pH range Table 4. Resistance to low pH of Lactobacillus isolates (log cfu/ml). Resistance to low pH (log cfu/ml) Lactobacillus Lactobacillus Lactobacillus Lactobacillus Lactobacillus salivarius brevis fermentum plantarum cellobiosus 2.0 1.15 ± 0.11a N 1.12 ±0.00a 1.00 ±0.00a 1.10 ±0.00a 3.0 1.22 ± 0.12a N 1.22 ±0.50a 1.20 ±0.22a 1.20 ±0.21a 4.0 1.30 ± 0.10a 1.34±0.00a 1.28 ±0.00a 1.22 ±0.03a 1.32 ±0.01a 1.22 ±0.11 1.34±0.00 1.21±0.16 1.14±0.08 1.21±0.07 Average abc *Means±SD; Means bearing different superscripts in the same column differ significantly (p>0.05); N negative. Antibiotic resistance All Lactobacillus isolates were tested for antibiotic resistance. According to the result obtained Lactobacillus plantarum, Lactobacillus cellobiosus and Lactobacillus brevis were the potent antibiotic resistant strains. Lactobacillus salivarius and Lactobacillus fermentum were not resistant to Gentamycin and Tetracycline respectively. Halami et al., (2000) reported that Lactobacillus spp are resistant to β-lactam, cephalosporin, aminoglycosides, quinolone, imidazole, nitrofurantoin and fluoroquinolines. Lactobacilli are generally resistant to aminoglycosides (Belletti et al., 2009). Table 5. Antibiotic resistance of Lactobacillus isolates. Antibiotic resistance Lactobacillus Lactobacillus Lactobacillus Lactobacillus Lactobacillus Antibiotics salivarius fermentum plantarum cellobiosus brevis Streptomycin R R R R R Gentamycin N R R R R Tetracycline R N R R R abc *Means±SD; Means bearing different superscripts in the same column differ significantly (p>0.05); R resistance, N negative. Resistance to bile acids All selected Lactobacillus isolates were screened for bile salt tolerance. Lactobacillus salivarius and Lactobacillus fermentum were survived with significant reduction in viable count but L. plantarum, L.cellobiosus and L.brevis were retaining their viability with negligible reduction after 4 h of exposure to 0.3 % (w/v) bile salt. This result indicated that, all strains can tolerate the bile salt 0.3 % (w/v) concentration with reduction in viable count. J. Biol. Chem. Research 72 Vol. 32, (1): 66-76 (2015) Isolation……………………………………………….………………Probiotic Ganguly, 2015 This is in agreement with Jensen et al., (2012) who reported that Lactobacillus spp. tolerate gastric juice well with no reduction in viability. Similarly Vitali et al., (2012) determined the probiotic potential of large number of lactic acid bacteria isolated from fruit and vegetables were survived in gastric and intestinal conditions. Table 6. Resistance to bile acids 0.3 % (w/v) of Lactobacillus isolates (log cfu/ml). Resistance to bile acids 0.3 % (w/v) Lactobacillus Lactobacillus Lactobacillus Lactobacillus Lactobacillus Time salivarius brevis fermentum plantarum cellobiosus 0h 1.42±0.11a 1.50±0.00a 2.51±0.00b 2.53±0.00b 2.65±0.00b 1h 1.00±0.00a 1.25±0.03a 2.41±0.00b 2.51±0.02b 2.63±0.00b 2h 0.78±0.02a 1.01±0.01a 2.40±0.00b 2.50±0.00b 2.50±0.03b 3h 0.35±0.00a 0.98±0.02a 2.35±0.00b 2.45±0.04b 2.48±0.00b Average 0.89±0.03 1.19±0.02 2.42±0.00 2.50±0.12 2.57±0.01 *Means±SD; abc Means bearing different superscripts in the same column differ significantly (p>0.05). Haemolytic test All isolates were tested for hemolytic activity and gave negative result. Kumar and Murugalatha, (2012) reported that LAB with α–haemolytic are safe for human use. This result agrees with Sandra et al., (2012) who reported that none of the fifteen putative probiotics was found to be β-hemolytic. This is also comparable with Estifanos H, (2014) who reported that all examined Lactobacillus strains isolated from curd were not exhibited β-hemolytic activity. Antibacterial activity of Lactobacillus isolates The selected five isolates of cell free supernatant (CFS) were tested for their antimicrobial activity against pathogenic microorganisms (P.aeruginosa, S.aureus, E.coli, and K.pneumonia). Results showed that all the CFSs were found to produce inhibition zone against pathogenic bacteria and significant differences among the isolates was shown. L.brevis was produce greater inhibition zone against the tested microorganism followed by L. cellobiosus, L. plantarum and the lowest antimicrobial effect was recorded in L. salivarius and L. fermentum isolates. This may be due to production of short-chain organic acids (lactic, acetic, propionic), bacteriocins (nisin, acidolina, acidofilina, lacatcyna, lacocydyna, reutryna, laktoline, entrocine) and hydrogen peroxide. Bacteriocins have a high antibacterial activity against Escherichia coli, Salmonella, Staphylococcus aureus, Clostridium perfringers, and Campylobacter (Patil, m.m., and Ajay pal, 2010 and Karimi R. et al., 2012). Similar result on antagonistic activity of LAB was reported by Hernandez et al., (2005) the CFS of the selected Lactobacillus isolates inhibited the growth of K. pneumoniae, S. aureus, and E. coli and (Abriouel et al.,2012) isolated from raw fruits, vegetables and human sources. J. Biol. Chem. Research 73 Vol. 32, (1): 66-76 (2015) Isolation……………………………………………….………………Probiotic Ganguly, 2015 Vitali et al., (2012) isolated lactobacillus strains from olives produced antimicrobial effect against S. aureus, E.facalis, Salmonella enteric. (Messaoudi, 2012) also reported that Lactobacillus strains isolated from chicken showed inhibition against L.monocytogenes, S.aureus and Salmonella. Table 7. Antimicrobial activity of Lactobacillus isolates (CFS). diameter of inhibition zone (mm) P. aeruginosa S. aureus Lactobacillus Isolates E. coli K. pneumonia L. salivarius 12 9 10 12 L. fermentum 13 10 12 12 L. plantarum 14 15 14 15 L. cellobiosus 22 20 21 22 L. brevis 25 24 25 23 CONCLUSION Lactic acid bacteria (LAB) are the most important bacteria concerning food fermentation, pharmaceutical and special dietary applications. Different lactic acid bacteria strains were isolated from various sources including fruits and vegetables, milk, and fermented foods. In the current study lactic acid bacteria strains were isolated from cabbage sample. According to physiological and biochemical test; L. salivarius, L.brevis, L. plantarum, L. cellobiosus, and L. fermentum were isolated from cabbage sample. Probiotic effect of all isolates were examined under conditions simulating human gastrointestinal (GI) tract included, antibiotic resistance, and resistance to low pH, resistance to bile acids, haemolytic and antimicrobial activity against pathogenic bacteria. According to antimicrobial test all Lactobacillus strains shown antagonistic effect against all pathogenic bacteria (P.aeruginosa, S.aureus, E.coli, and K.pneumonia) with different degree of inhibitory. Among all isolates L.brevis shown more inhibition zone followed by Lactobacillus cellobiosus and L. plantarum. According to resistance to bile, Lactobacillus salivarius and Lactobacillus fermentum were survived with significant (p<0.05) reduction in viable count but L.plantarum, L.cellobiosus and L.brevis were retaining their viability with negligible reduction. According to resistance to low pH, L.plantarum, L.cellobiosus, L.salivarius and L.brevis were able to survive at pH ranging from 2 to 4 with significant reduction in viable count. According to haemolytic test all isolates did not exhibited β–haemolytic activity when grown in Colombia human blood agar. In conclusion, the current study indicated that L.brevis and L.cellobiosus can be used as potential probiotic Lactobacillus strains among all isolates. ACKNOWLEDGEMENTS The authors would like to acknowledge the Department of Biology, College of Natural and Computational Sciences, Haramaya University, Ethiopia for providing us all microbiology laboratory facilities required to conduct this research project. J. Biol. Chem. Research 74 Vol. 32, (1): 66-76 (2015) Isolation……………………………………………….………………Probiotic Ganguly, 2015 REFERENCES Abriouel, H., Benomar, N., Cobo, A., Caballero, N., Fuentes, M.A., Pérez-Pulido, R. and Gálvez, A. 2012. 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Corresponding author: Estifanos Hawaz, Department of Biology, College of Natural and Computational Sciences, Haramaya University, Ethiopia Email: [email protected] Tel.: +251939589792 J. Biol. Chem. Research 76 Vol. 32, (1): 66-76 (2015)